István T. Horváth

Facile catalyst separation without water : fluorous biphase hydroformylation of olefins

A novel concept for performing stoichiometric and catalytic chemical transformations has been developed that is based on the limited miscibility of partially or fully fluorinated compounds with nonfluorinated compounds. A fluorous biphase system (FBS) consists of a fluorous phase containing a dissolved reagent or catalyst and another phase, which could be any common organic or nonorganic solvent with limited or no solubility in the fluorous phase. The fluorous phase is defined as the fluorocarbon (mostly perfluorinated alkanes, ethers, and tertiary amines)—rich phase of a biphase system. An FBS compatible reagent or catalyst contains enough fluorous moieties that it will be soluble only or preferentially in the fluorous phase. The most effective fluorous moieties are linear or branched perfluoroalkyl chains with high carbon number; they may also contain heteroatoms. The chemical transformation may occur either in the fluorous phase or at the interface of the two phases. The application of FBS has been demonstrated for the extraction of rhodium from toluene and for the hydroformylation of olefins. The ability to separate a catalyst or a reagent from the products completely at mild conditions could lead to industrial application of homogeneous catalysts or reagents and to the development of more environmentally benign processes.

Valorization of Biomass: Deriving More Value from Waste

Most of the carbon-based compounds currently manufactured by the chemical industry are derived from petroleum. The rising cost and dwindling supply of oil have been focusing attention on possible routes to making chemicals, fuels, and solvents from biomass instead. In this context, many recent studies have assessed the relative merits of applying different dedicated crops to chemical production. Here, we highlight the opportunities for diverting existing residual biomass—the by-products of present agricultural and food-processing streams—to this end.

γ-Valerolactone—a sustainable liquid for energy and carbon-based chemicals

We propose that γ-valerolactone (GVL), a naturally occurring chemical in fruits and a frequently used food additive, exhibits the most important characteristics of an ideal sustainable liquid, which could be used for the production of both energy and carbon-based consumer products. GVL is renewable, easy and safe to store and move globally in large quantities, has low melting (−31 °C), high boiling (207 °C) and open cup flash (96 °C) points, a definitive but acceptable smell for easy recognition of leaks and spills, and is miscible with water, assisting biodegradation. We have established that its vapor pressure is remarkably low, even at higher temperatures (3.5 kPa at 80 °C). We have also shown by using 18O-labeled water that GVL does not hydrolyze to gamma-hydroxypentanoic acid under neutral conditions. In contrast, after the addition of acid (HCl) the incorporation of one or two 18O-isotopes to GVL was observed, as expected. GVL does not form a measurable amount of peroxides in a glass flask under air in weeks, making it a safe material for large scale use. Comparative evaluation of GVL and ethanol as fuel additives, performed on a mixture of 10 v/v% GVL or EtOH and 90 v/v% 95-octane gasoline, shows very similar properties. Since GVL does not form an azeotrope with water, the latter can be readily removed by distillation, resulting in a less energy demanding process for the production of GVL than that of absolute ethanol. Finally, it is also important to recognize that the use of a single chemical entity, such as GVL, as a sustainable liquid instead of a mixture of compounds, could significantly simplify its worldwide monitoring and regulation.

Handbook of fluorous chemistry

Preface.1. Fluorous Chemistry: Scope and Definition (I. Horvath, et al.).2. A Personal View of the History of Fluorous Chemistry (I. Horvath).3. Fluorous Solvents and Related Media (J. Gladysz & C. Emnet).4. Strategies for the Recovery of Fluorous Catalysts and Reagents: Design and Evaluation (J. Gladysz & R. Correa de Costa).5. Ponytails: Structural and Electronic Considerations (J. Gladysz).6. Partition Coefficients Involving Fluorous Solvents (J. Gladysz, et al.).7. Separations with Fluorous Silica Gel and Related Materials (D. Curran).8. Light Fluorous Chemistry-A User-s Guide (D. Curran).9. Getting Started in Synthesis: A Tabular Guide to Selected Monofunctional Fluorous Compounds (J. Rabai).10. Highlights of Applications in Synthesis and Catalysis.11. Preparations.12. Applications of Fluorous Compounds in Materials Chemistry.13. Fluorous Materials for Biomedical Uses (J. Riess).14. Fun and Games with Fluorous Chemistry (J. Rabai).Index.

Multiphase homogeneous catalysis

Preface. Contributors. Volume 1. 1 Introduction (Boy Cornils, Wolfgang A. Herrmann, Istvan T. Horvath, Walter Leitner, Stefan Mecking, Helene Olivier-Bourbigou, and Dieter Vogt). 2 Aqueous-Phase Catalysis (Boy Cornils and Wolfgang A. Herrmann). 2.1 Introduction (Boy Cornils). 2.2 State-of-the-Art. 2.3 Homogeneous Catalysis in the Aqueous Phase as a Special Unit Operation. 2.4 Typical Reactions. 2.5 Commercial Applications. 2.6 Supported Aqueous-Phase Catalysis as the Alternative Method (Henri Delmas, Ulises Jauregui-Haza, and Anne-Marie Wilhelm). 2.7 The Way Ahead: What Should be Done in the Future? (Boy Cornils and Wolfgang A. Herrmann). 3 Organic-Organic Biphasic Catalysis (Dieter Vogt). 3.1 Introduction (Dieter Vogt). 3.2 State-of-the-Art and Typical Reactions. 3.3 Economical Applications (SHOP Process) (Dieter Vogt). 3.4 Conclusions and Outlook (Dieter Vogt). 4 Fluorous Catalysis (Istvan T. Horvath). 4.1 Introduction (Istvan T. Horvath). 4.2 State-of-the-Art and Typical Reactions. 4.3 Concluding Remarks (Istvan T. Horvath). Volume 2. 5 Catalysis in Nonaqueous Ionic Liquids (ILs) (Helene Olivier-Bourbigou). 5.1 General Introduction (Yves Chauvin). 5.2 State-of-the-Art. 5.3 Commercial Applications and Aspects. 5.4 Preliminary (Eco-)Toxicological Risk Profiles of Ionic Liquids (Johannes Ranke, Frauke Stock, Reinhold Stormann, Kerstin Molter, Jens Hoffmann, Bernd Ondruschka, and Bernd Jastorff). 5.5 Concluding Remarks and Outlook (Helene Olivier-Bourbigou). 6 Catalysis using Supercritical Solvents (Walter Leitner). 6.1 Introduction (Aaron M. Scurto). 6.2 State-of-the-Art (Applications of SCFs in Areas other than Catalysis) (Nils Theyssen). 6.3 Homogeneous Catalysis in Supercritical Solvents as a Special Unit Operation (Charles M. Gordon and Walter Leitner). 6.4 Typical Reactions. 6.5 Economics and Scale-Up (Peter Licence and Martyn Poliakoff). 6.6 The Way Ahead: What Should be Done in the Future? (Walter Leitner). 7 Soluble Polymer-Bound Catalysts (Stefan Mecking). 7.1 Introduction (Stefan Mecking). 7.2 State-of-the-Art (Stefan Mecking). 7.3 Homogeneous Catalysis with Soluble Polymer-Bound Catalysts as a Unit Operation (Stefan Mecking). 7.4 Typical Reactions. 7.5 Toward Economic Applications (Uwe Dingerdissen and Juan Almena). 7.6 What Should be Done in the Future? (Stefan Mecking). 8 Multiphase Processes as the Future of Homogeneous Catalysis (Boy Cornils and Wolfgang A. Herrmann). Subject Index.

Molecular mapping of the acid catalysed dehydration of fructose

Several intermediates and different reaction paths were identified for the acid catalysed conversion of fructose to 5-(hydroxymethyl)-2-furaldehyde (HMF) in different solvents. The structural information combined with results of isotopic-labelling experiments allowed the determination of the irreversibility of the three steps from the fructofuranosyl oxocarbenium ion to HMF as well as the analogous pyranose route.

First ring-opening metathesis polymerization in an ionic liquid. Efficient recycling of a catalyst generated from a cationic ruthenium allenylidene complex

Ring-opening metathesis polymerization (ROMP) of norbornene was carried out in a biphasic medium consisting of the ionic liquid [bdmim][PF6] and toluene with a cationic ruthenium allenylidene precatalyst. The ionic liquid contained the ruthenium allenylidene complex and toluene dissolved the formed polymer. Both the catalyst and the ionic liquid were reused several times and led to very good polymer yields.

High-pressure NMR studies of the water soluble rhodium hydroformylation system

Rh(CO)2(acac) reacts with P(m-C6H4SO3Na.H2O)3 (P/Rh > 3.5) in water under CO to give HRh(CO)[P(m-C6H4SO3Na)3]3 (1a), the structure of which is similar to HRh(CO) (PPh3)3 (1b). High pressure NMR spectra of an aqueous solution containing1a and three molar excess of P(m-C6H4SO3Na)3 does not show the formation of new species up to 200 atm of CO∶H2(1∶1). In contrast,1b, in the presence of three molar excess of PPh3, is completely converted to HRh(CO)2(PPh3)2 (2b) under 30 atm CO/H2(1∶1) in toluene. The activation energy of the dissociation of P(m-C6H4SO3Na)3 from1a in water was found to be 30±1 kcal/mol, which is 11±1 kcal/mol higher than the dissociation of PPh3 from1b in toluene.

Hydroformylation of olefins with the water soluble HRh(CO)[P(m-C6H4SO3Na)3]3 in supported aqueous-phase. Is it really aqueous?

The hydroformylation of olefins with the water soluble complex HRh(CO) [P(m-C6H4SO3Na)3]3 (1) is dependent on the solubility of the olefins in the aqueous phase. In contrast, when the aqueous solution of1 is immobilized on a high surface area silica support the effects of the size of the olefins diminish. The immobilized catalyst1 on silica shows significant water loss but not rhodium leaching. It is proposed that the hydrophilic support holds the water soluble phosphines by hydrogen bonding of the hydrated sodium-sulphonate groups to the surface.

A new definition of the intermediate group of gamma-ray bursts

Gamma-ray bursts can be divided into three groups (short, intermediate, long) with respect to their durations. This classification is somewhat imprecise, since the subgroup of intermediate duration has an admixture of both short and long bursts. In this paper a physically more reasonable definition of the intermediate group is presented, using also the hardnesses of the bursts. It is shown again that the existence of the three groups is real, no further groups are needed. The intermediate group is the softest one. From this new definition it follows that 11% of all bursts belong to this group. An anticorrelation between the hardness and the duration is found for this subclass in contrast to the short and long groups. Despite this difference it is not clear yet whether this group represents a physically different phenomenon.